Etiological and epidemiological features of acute respiratory infections in China.

Nationwide prospective surveillance of all-age patients with acute respiratory infections was conducted in China between 2009‒2019. Here we report the etiological and epidemiological features of the 231,107 eligible patients enrolled in this analysis. Children <5 years old and school-age children have the highest viral positivity rate (46.9%) and bacterial positivity rate (30.9%). Influenza virus, respiratory syncytial virus and human rhinovirus are the three leading viral pathogens with proportions of 28.5%, 16.8% and 16.7%, and Streptococcus pneumoniae, Mycoplasma pneumoniae and Klebsiella pneumoniae are the three leading bacterial pathogens (29.9%, 18.6% and 15.8%). Negative interactions between viruses and positive interactions between viral and bacterial pathogens are common. A Join-Point analysis reveals the age-specific positivity rate and how this varied for individual pathogens. These data indicate that differential priorities for diagnosis, prevention and control should be highlighted in terms of acute respiratory tract infection patients' demography, geographic locations and season of illness in China.

Abnormal apelin-ACE2 and SGLT2 signaling contribute to adverse cardiorenal injury in patients with COVID-19.

BACKGROUND: Angiotensin converting enzyme 2 (ACE2) has recently been identified as the functional receptor for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the causative agent response for novel coronavirus disease 2019 (COVID-19). This study aimed to explore the roles of ACE2, apelin and sodium-glucose cotransporter 2 (SGLT2) in SARS-CoV-2-mediated cardiorenal damage. METHODS AND RESULTS: The published RNA-sequencing datasets of cardiomyocytes infected with SARS-CoV-2 and COVID-19 patients were used. String, UMAP plots and single cell RNA sequencing data were analyzed to show the close relationship and distinct cardiorenal distribution patterns of ACE2, apelin and SGLT2. Intriguingly, there were decreases in ACE2 and apelin expression as well as marked increases in SGLT2 and endothelin-1 levels in SARS-CoV-2-infected cardiomyocytes, animal models with diabetes, acute kidney injury, heart failure and COVID-19 patients. These changes were linked with downregulated levels of interleukin (IL)-10, superoxide dismutase 2 and catalase as well as upregulated expression of profibrotic genes and pro-inflammatory cytokines/chemokines. Genetic ACE2 deletion resulted in upregulation of pro-inflammatory cytokines containing IL-1ß, IL-6, IL-17 and tumor necrosis factor α. More importantly, dapagliflozin strikingly alleviated cardiorenal fibrosis in diabetic db/db mice by suppressing SGLT2 levels and potentiating the apelin-ACE2 signaling. CONCLUSION: Downregulation of apelin and ACE2 and upregulation of SGLT2, endothelin-1 and pro-inflammatory cytokines contribute to SARS-CoV-2-mediated cardiorenal injury, indicating that the apelin-ACE2 signaling and SGLT2 inhibitors are potential therapeutic targets for COVID-19 patients.

Development, performance evaluation, and clinical application of a Rapid SARS-CoV-2 IgM and IgG Test Kit based on automated fluorescence immunoassay.

The ongoing coronavirus disease 2019 (COVID-19) epidemic has made a huge impact on health, economies, and societies all over the world. Although reverse transcription-polymerase chain reaction (RT-PCR)-based nucleic acid detection has been primarily used in the diagnosis of COVID-19, it is time-consuming with limited application scenarios and must be operated by qualified personnel. Antibody test, particularly point-of-care antibody testing, is a suitable complement to nucleic acid test as it provides rapid, portable, and cost-effective detection of infections. In this study, a Rapid Antibody Test Kit was developed based on fluorescence immunochromatography for the sensitive, accurate, and automated detection of immunoglobulin M (IgM) and IgG antibodies against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in human serum, plasma, and whole blood samples within 10 min. The sensitivity, specificity, precision, and stability of the test kit were of good performance. No cross-activity and no interference was observed. In the multiple-center parallel study, 223 samples from hospitalized patients were used to evaluate the clinical specificity of the test. Both SARS-CoV-2 IgM and IgG achieved a clinical specificity of 98.21%. The clinical sensitivities of SARS-CoV-2 IgM and IgG were 79.54% and 87.45%, respectively, among 733 reverse transcription-polymerase chain reaction (RT-PCR) confirmed SARS-CoV-2 samples. For the combined IgM and IgG assays, the sensitivity and specificity were 89.22% and 96.86%, respectively. Our results demonstrate that the combined use of IgM and IgG could serve as a more suitable alternative detection method for patients with COVID-19, and the developed kit is of great public health significance for the prevention and control of the COVID-19 pandemic.